Covaxin safe, ‘immunogenic with no serious side effects’: Lancet study

The phase 1 trial results published in The Lancet in January showed the vaccine was well tolerated in all dose groups with no related serious adverse events

The Lancet on Tuesday published interim phase 2 trial results of Bharat Biotech’s Covid-19 vaccine­— Covaxin— that shows a two-fold increase in antibody titres than phase 1. Side-effects were observed in 10-12% of participants, which is six times less than other Covid-19 vaccines in use.

A health worker shows Bharat Biotech’s Covaxin ahead of the nationwide Covid-19 vaccine roll out, in Pune on January 15. (HT file)

Also, the phase 1 study follow-up showed durable antibody and T-cell response for three months post-vaccination.

The phase 1 trial results published in The Lancet in January showed the vaccine was well tolerated in all dose groups with no related serious adverse events.

For phase 2 trials, two intramuscular doses were administered four weeks apart to 380 participants across nine hospitals in nine states in a double-blind, randomised, and multicentre manner to evaluate the immunogenicity and safety of Covaxin.

Bharat Biotech has developed the whole-virion inactivated SARS-CoV-2 vaccine candidate (BBV152) in collaboration with the Indian Council of Medical Research (ICMR).

The virus strain (NIV-2020-770) containing the Asp614Gly mutation, isolated from a Covid-19 patient who came in from Wuhan (China), and sequenced at the ICMR-National Institute of Virology (NIV), was provided to Bharat Biotech in May last year.

The vaccine was approved for use in India on January 3 based on its safety and immunogenicity results and also efficacy shown in animal studies. Apart from Covaxin, Oxford-AstraZeneca’s vaccine locally manufactured by Serum Institute of India as Covishield is currently approved for use in India.

At least 20 million doses have been administered of the two vaccines during the national the immunisation drive since January 16.

“Between Sept 5 and 12, 2020, 921 participants were screened, of whom 380 were enrolled… In the phase 2 trial, BBV152 showed better reactogenicity and safety outcomes, and enhanced humoral and cell-mediated immune responses compared with the phase 1 trial. The 6 μg with Algel-IMDG formulation has been selected for the phase 3 efficacy trial,” the paper published in the Lancet said.

The paper added participants were healthy adults and adolescents (aged 12–65) even as neither Bharat Biotech nor ICMR have made public the number of participants below 18 in the clinical trials.